Cyclic lipopeptides, generally hexapeptides, have been obtained as secondary metabolites on the cultivation of certain fungi and have been reported to be antifungal agents, especially against Candida species. In addition, semi-synthetic cyclic lipopeptides obtained by deacylation of the lipophilic side chain of a natural cyclic lipopeptide and then reacylating to obtain novel unnatural cyclic lipopeptides have also been reported to be useful against Candida species.
These compounds are oftentimes referred to in the art as echinocandin type compounds. These compounds are reported as amorphous solids or as films. No cyclic lipopeptide has been obtained in crystalline form. For ultimate utilization in therapy, it is desirable that the compound be of sufficient purity to be in crystalline form.
A particularly useful cyclic lipopeptide being highly effective against Pneumocystis carinii, the causative agent of pneumocystis pneumonia as well as having superior properties as an antifungal agent, is a compound (seq. ID No: 1) having the following formula (I): ##STR2## The compound of formula (I) (hereinafter also Compound I) is the subject of copending application Ser. Nos. 07/492,025 filed on Mar. 12, 1990, and 07/492,026, filed on Mar. 12, 1990, now U.S. Pat. No. 5,021,341, issued on Jun. 4, 1991 and may be named
1-[4,5-dihydroxy-N.sup.2 -(10,12-dimethyl-1-oxotetradecyl) ornithine]-5-(3-hydroxy-glutamine)-6-(3-hydroryproline)echinocandin B. The preferred stereoisomer is thought to be: 1-[4R,5R-dihydroxy N.sup.2 -(10,12-dimethyl-1-oxotetradecyl)-L-ornithine]-5-(3R-hydroxy-L-glutamine)- 6-[3S-hydroxy-L-proline]echinocandin B. This compound also had not been obtained in crystalline form.